Recent achievements in pressure compensation technology as presented in the co-pending patent application Ser. No. 07/085,336 have made it possible to adapt or produce devices for underwater operation which do not require the use of extensive pressure hulls and high pressure seals. However the devices still require a waterproof construction.
The classical approach for solving the dilemma posed by a need to operate an apparatus underwater when the apparatus is not normally designed for immersion has been the use of a pressure hull. Such devices are bulky, costly and inordinately complex when the device has numerous push-button controls or knobs that have to be activated by an operator. Some attempts have been made to solve this problem by providing a flexible, waterproof container with optical windows when necessary. Thus such devices may be used to encase a video camera, especially the type with push-button controls and the operator may utilize the device underwater. Unfortunately, this approach is severely limited by pressure considerations. At moderate depths, the pressure exerted on the flexible container becomes so great that push-buttons are activated and controls jammed. An even greater problem with this approach is that at moderate depths, the structure of the protected device becomes deformed and in many instances destroyed by the outside water pressure.
Another very serious difficulty encountered by flexible, waterproof containers is that sharp edges of the apparatus contained therein often penetrate the waterproof barrier as the result of external water pressure. Such penetrations allow sea water to enter the container and destroy the apparatus therein.